Generic substitution was introduced in Norway in 2001, and the sale of these drugs had, by 2008, reached 40% of the market shares in defined daily doses. Little is known whether generic substitution causes a poorer adherence than before in chronic patients or to what extent it can be a source of error when nurses handle medications. In three studies presented in this proceeding article patients on antihypertensive therapy and nurses in a big hospital were interviewed to look into this problem. The results from the studies show that generic substitution is an additional challenge both for the patients and for the nurses. The patients feel insecure about the situation, and it was even found that one in twenty took the brand product as well as the non-branded substituted product at the same time. In general they at least wished that they had had some information from their doctor before they came to the pharmacy. Also the nurses felt insecure and claimed not to have the knowledge needed to perform generic substitution. They felt that their role in being responsible for the changes for the patients easily could be a source of medication errors, and that the situation would probably ameliorate if the doctors prescribed the hospital's preferred drugs.